diff --git a/src/librlibc/lib.rs b/src/librlibc/lib.rs
index 3e45964cd12..c7295125f42 100644
--- a/src/librlibc/lib.rs
+++ b/src/librlibc/lib.rs
@@ -21,22 +21,26 @@
 //! the system libc library.
 
 #![crate_name = "rlibc"]
+#![experimental]
 #![license = "MIT/ASL2"]
 #![crate_type = "rlib"]
 #![doc(html_logo_url = "http://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "http://www.rust-lang.org/favicon.ico",
        html_root_url = "http://doc.rust-lang.org/master/")]
-#![feature(intrinsics)]
 
+#![feature(intrinsics, phase)]
 #![no_std]
-#![experimental]
 
 // This library defines the builtin functions, so it would be a shame for
 // LLVM to optimize these function calls to themselves!
 #![no_builtins]
 
-#[cfg(test)] extern crate std;
 #[cfg(test)] extern crate native;
+#[cfg(test)] extern crate test;
+#[cfg(test)] extern crate debug;
+
+#[cfg(test)] #[phase(plugin, link)] extern crate std;
+#[cfg(test)] #[phase(plugin, link)] extern crate core;
 
 // Require the offset intrinsics for LLVM to properly optimize the
 // implementations below. If pointer arithmetic is done through integers the
@@ -102,4 +106,100 @@
     return 0;
 }
 
-#[test] fn work_on_windows() { } // FIXME #10872 needed for a happy windows
+#[cfg(test)]
+mod test {
+    use core::option::{Some, None};
+    use core::iter::Iterator;
+    use core::collections::Collection;
+    use core::str::StrSlice;
+    use core::slice::{MutableVector, ImmutableVector};
+
+    use super::{memcmp, memset, memcpy, memmove};
+
+    #[test]
+    fn memcmp_single_byte_pointers() {
+        unsafe {
+            assert_eq!(memcmp(&0xFAu8, &0xFAu8, 1), 0x00);
+            assert!(memcmp(&0xEFu8, &0xFEu8, 1) < 0x00);
+        }
+    }
+
+    #[test]
+    fn memcmp_strings() {
+        {
+            let (x, z) = ("Hello!", "Good Bye.");
+            let l = x.len();
+            unsafe {
+                assert_eq!(memcmp(x.as_ptr(), x.as_ptr(), l), 0);
+                assert!(memcmp(x.as_ptr(), z.as_ptr(), l) > 0);
+                assert!(memcmp(z.as_ptr(), x.as_ptr(), l) < 0);
+            }
+        }
+        {
+            let (x, z) = ("hey!", "hey.");
+            let l = x.len();
+            unsafe {
+                assert!(memcmp(x.as_ptr(), z.as_ptr(), l) < 0);
+            }
+        }
+    }
+
+    #[test]
+    fn memset_single_byte_pointers() {
+        let mut x: u8 = 0xFF;
+        unsafe {
+            memset(&mut x, 0xAA, 1);
+            assert_eq!(x, 0xAA);
+            memset(&mut x, 0x00, 1);
+            assert_eq!(x, 0x00);
+            x = 0x01;
+            memset(&mut x, 0x12, 0);
+            assert_eq!(x, 0x01);
+        }
+    }
+
+    #[test]
+    fn memset_array() {
+        let mut buffer = [b'X', .. 100];
+        unsafe {
+            memset(buffer.as_mut_ptr(), b'#' as i32, buffer.len());
+        }
+        for byte in buffer.iter() { assert_eq!(*byte, b'#'); }
+    }
+
+    #[test]
+    fn memcpy_and_memcmp_arrays() {
+        let (src, mut dst) = ([b'X', .. 100], [b'Y', .. 100]);
+        unsafe {
+            assert!(memcmp(src.as_ptr(), dst.as_ptr(), 100) != 0);
+            let _ = memcpy(dst.as_mut_ptr(), src.as_ptr(), 100);
+            assert_eq!(memcmp(src.as_ptr(), dst.as_ptr(), 100), 0);
+        }
+    }
+
+    #[test]
+    fn memmove_overlapping() {
+        {
+            let mut buffer = [ b'0', b'1', b'2', b'3', b'4', b'5', b'6', b'7', b'8', b'9' ];
+            unsafe {
+                memmove(&mut buffer[4], &buffer[0], 6);
+                let mut i = 0;
+                for byte in b"0123012345".iter() {
+                    assert_eq!(buffer[i], *byte);
+                    i += 1;
+                }
+            }
+        }
+        {
+            let mut buffer = [ b'0', b'1', b'2', b'3', b'4', b'5', b'6', b'7', b'8', b'9' ];
+            unsafe {
+                memmove(&mut buffer[0], &buffer[4], 6);
+                let mut i = 0;
+                for byte in b"4567896789".iter() {
+                    assert_eq!(buffer[i], *byte);
+                    i += 1;
+                }
+            }
+        }
+    }
+}